Orthogonal Frequency Division Multiplexing (OFDM) is a transmission scheme that has been widely used in recent wireless communications because the OFDM is robust against multipath fading even though the OFDM uses a simple equalizer. An OFDM scheme has been adopted and used in a variety of wireless communication systems, such as a Wireless Local Access Network (WLAN), a Wireless Metropolitan Area Network (WMAN), a Digital Audio Broadcasting (DAB), a Digital Video Broadcasting (DVB), and the like.
However, an OFDM signal generally has a very high Peak-to-Average Power Ratio (PAPR) at a transmitting end. As such, if the PAPR increases, nonlinear distortion is caused by a power amplifier (PA) of a transmitter. An OFDM signal is very sensitive to the nonlinear distortion during operations. At this time, if power is not sufficiently backed off from a peak, a frequency spectrum of a communication system is widened and distortion is caused by inter-frequency modulation. As a result, the performance of the communication system is degraded.